1. Field of the Invention
The invention relates to methods and devices useful for analyzing crystalline content of molecules. More specifically, the methods and devices may be used to analyze crystalline content of molecules without having to isolate a precipitate or crystal of the molecule from an experiment.
2. Description of Related Art
X-ray crystallographic structure data from molecules, particularly macromolecules such as proteins and nucleic acid structures, are invaluable to structural biology. A general description of how high resolution X-ray crystal protein structures are obtained and refined from raw diffraction patterns of diffraction quality crystals and crystallization methods therefore is found in Creighton, T., Proteins, 2d Ed. (1993) W. H. Freeman & Co., New York.
Structural biology is a discipline that studies the correlation of molecular form and function in molecular, cell, and organismal biology and physiology. More detailed practical information on obtaining diffraction grade biomacromolecule crystals, specifically protein and protein-ligand co-crystals, may be found in McRee, D. and David. P., Practical Protein Crystallography, 2nd Ed. (1999), Academic Press Inc.
One of the challenges associated with obtaining X-ray crystallographic structure data for a molecule is the formation of crystals that, upon diffraction, can yield X-ray crystallographic structure data effective for solving the structure of the molecule.
A further challenge associated with obtaining X-ray crystallographic structure data is the isolation and manipulation of crystals once they are successfully formed. Biomacromolecule crystals are typically removed from the crystallization vessel and mounted for collection of sufficient X-ray diffraction data to determine the diffraction quality of the crystals.
Without the aid of the present invention, mechanically fragile macromolecule crystals are removed from the container in which the crystals are formed and then are mounted prior to obtaining diffraction data. The handling involved in the isolation and mounting process can damage the crystals such that they are not of insufficient quality for X-ray crystallography. Even the diffraction experiment determining crystal quality can damage the crystal. Thus, any re-mounting required, for example when the crystals are mounted in a manner incompatible with cryogenic storage, can render the heretofore diffraction quality crystal useless for X-ray crystallography. Typically protein crystals are mounted for data collection in thin-walled glass capillaries or fiber loops. Several techniques for mounting biomacromolecule crystals in a capillary exist in which crystals are isolated from a previous growing location and put into the mother liquor of the crystals, or another solution resembling the solution in which the crystals were grown.
In addition to being relatively physically fragile, compared to crystals of other molecules, biomacromolecule crystals such as protein crystals are relatively susceptible to thermal degradation as well as deterioration as a result of microorganism growth. Thus protein crystals are typically stored under liquid nitrogen, in the presence of a cryoprotectant, which protects the typically hydrated protein crystal from damaging effects of the low temperatures, further complicating their manipulation (Rubinson et al. (2000) Acta Crystallogr. D Biol. Crystallogr.: 56:996–1001; and generally McRee, D. and David. P., Practical Protein Crystallography, 2nd Ed. (1999), Academic Press Inc.).